How to Press Rosin Using Double Bag Tech

Pressing that sweet, sweet rosin out of your flower or hash never gets old. It is something we can all do at home. Part of the fun is experimenting with new ways to produce rosin. Some of us started with a hair straightener or an iron. Some do not use rosin bags when pressing their flower. Others found a deep passion and got themselves a proper rosin press. Many who use rosin bags choose lower micron sizes (i.e. 25u, 37u) for hash and higher micron sizes (i.e. 120u, 160u) for flower.

Now we are seeing a new tech, the Double Bag Tech, in which extractors use two bags, one inside the other, for a single press. We here at Gutenberg’s Dank Pressing Co reached out to some experts in the field who use the double bag tech to pick their brains about how to do the double bag tech and what advantages and disadvantages there are. Let’s see what they had to say:

Double Rosin Bag Tech

Double Rosin Bag Tech Infograph
(Double Bag Tech by Gutenberg’s Dank Pressing Co)

Advantages of Double Rosin Bag Tech

As knowledge is passed from hash masker to hash maker, the community continues to grow. We are very thankful to our four experts who helped us with this article. When asked the reason they use the double bag tech, each of them cited stability as the main reason. Homegrown advocate, @Pleasantly.Pressed,  explains that “Pressing water hash in a 25u at a low temp, there’s [a lot] of pressure on the bag trying to force the oils out . . . If you press your hash too long you degrade the material . . . but if you press too fast you can get a blow out”. So the double bag tech adds stability allowing you to “get the press done quicker with less risk of blowout”. 

Chris Killiger (@SolventlessNH), Lab Manager at Prime Alternative Treatment Centers of NH, sees it as a fiscal decision. Use one bag and risk a blowout, ruining how ever much starting material you used. Or double bag it, reduce blowout risk, get more rosin. Hash maker, @Desert.Heat.Extracts, explained to us that hash expands a lot when pressed and, relative to flower, there is a lot of oil trying to come through very fine filters. The strain on the nylon in the filters is immense and a 2nd bag helps maintain structural integrity. 


Our pal, @HeadyHoarder, uses a double bag to produce a “far cleaner” final product as well as “lower chances of blowouts”. One concern of his is melt coming through a single bag into the finished product. So in addition to stability, @HeadyHoarder finds the double bag tech adds additional filtration leading to a better quality end product.

double rosin bag tech
(Image from: SolventlessNH)

Disadvantages of Double Bag Tech

Extra stability (less blowouts) and a cleaner product are the advantages of the double bag tech, but what about any disadvantages? Everyone agreed that the possibility of a lower yield and additional bag costs could be a negative factor. But as Chris explained, “it’s in no way worth the risk of blowing out a single bag just to save a couple dollars on a second bag”. 

Choosing Micron Sizes

(Image from: @HeadyHoarder)

Choosing which micron size bag has to do with your starting material, and then a bit of preference. For pressing flower, most use a single bag (90u – 220u). Hash and dry sift require lower micron bags to really filter the material (25u and 37u are the most common). When applying the double bag tech, the inside bag should be the lower micron of the two (i.e. a 25u inside a 90u).

@HeadyHoarder has found 25u inside another 25u to be the most common bag pairing. But as we said, preference has a lot to do with which bags you choose. @Desert.Heat.Extracts has also found 25u inside 25u to be common, but personally he has had blowouts with this bag combo. He uses a 25u inside a 120u-160u bag to, in his opinion, increase stability and decrease the chances of a blowout.

Both Chris (@SolventlessNH), and @HeadyHoarder find that having both bags on the lower micron (25u, 37u) side of things works best for their presses.

“Most of the contaminate will be contained by the first bag, the second bag is just minor refining and preventing blowouts. I’ve seen many times the inner bag blew out into the outside one and was contained” – (@HeadyHoarder)

Chris uses a unique technique for pressing hash where he uses two 37u rosin bags that are flipped inside out. According to Chris, this leaves plenty of room for the hash to expand and let the oil “flow” from the hash, and not get “pushed” out as with a flower press.

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